1. Field of the Invention
The invention relates to an instrument and method for manipulating an operating member that is attached to suture material while maintaining tension on the suture material.
2. Description of the Related Art
In many anatomical structures, soft tissue, such as tendons and ligaments, are inserted into bone tissue through small collagenous fibers. Such structures are very strong thus permitting muscles to affect force on the bone through the tendons or permitting the ligaments to stabilize the bone. Notwithstanding the strength of such structures, various injuries and degeneration often occur in which the soft tissue is torn away from the bone. Various procedures have been developed for reattaching soft tissue to bone tissue.
For example, it is known to utilize screws, staples, cement, or suture material to attach soft tissue to bone tissue. It is also known to insert a suture anchor into a cavity formed in bone tissue. Typically, a suture anchor has sharp burrs, threads, or the like which engage with or bite into surfaces defining the cavity in the bone tissue, and a portion to which a length of suture material is attached. The other end of the suture material is coupled to soft tissue by suturing, tying, or another procedure before or after insertion of the suture anchor into the cavity. Accordingly, soft tissue or the like can be attached to bone tissue to repair damage. However, often density of bone tissue is very low thus rendering it difficult to securely fix an anchor in a bone cavity.
For example, it often is desirable to reattach tendons or other soft tissue to the humerus. However, in most people over the age of 30, the cancellous bone in the humerus has absorbed to the point where the density of the bone is very low and, in some cases, only the cortical bone remains. Of course, when bone density is very low, the strength of the bone tissue is also relatively low and thus it is difficult to reliably fix an anchor to the bone tissue by embedding the anchor in a cavity formed in the bone.